Why Does My EV Charger Keep Tripping? RCD & Fault Guide
Why Does My EV Charger Keep Tripping?
Quick diagnosis: when does it trip?
| Pattern | Likely cause |
|---|---|
| Trips immediately, every single time you plug in | Likely a genuine earth fault, damaged cable, or a fault in the vehicle itself |
| Trips randomly, no clear pattern | Could be a marginal earth leakage issue, an ageing protection device, or intermittent moisture ingress |
| Only trips when it's raining or damp | Moisture ingress into the charger, cable, or connector — check enclosure seals and IP rating |
| Only trips during scheduled/overnight charging | Possible PEN fault condition or supply-related issue that's more likely to surface under sustained load |
| Started tripping after a storm or power cut | Possible surge event — check for surge protection device (SPD) damage |
Common causes, explained
RCD trips
An RCD (Residual Current Device) trips when it detects current leaking to earth rather than returning through the expected circuit — even a small imbalance, as little as 30mA, will trip a standard RCD. This is a safety feature working correctly, not a fault in itself, but repeated tripping means something is causing that leakage. Read our full guide on RCD trip sensitivity (30mA vs 100mA vs 300mA) to understand which rating your installation should have.
RCBO trips
An RCBO combines RCD earth-fault protection with MCB overcurrent protection in one device. If your charger's RCBO trips, it's worth noting whether it trips instantly (pointing to an earth fault) or after a delay under sustained load (pointing to an overcurrent condition, such as the circuit being asked to carry more current than it's rated for).
Earth leakage
Small amounts of earth leakage are normal in most electrical systems, but EV chargers can be particularly sensitive to it because charging sessions run at high, sustained current for long periods, giving any marginal leakage more opportunity to accumulate and trip the RCD. This is one reason correctly rated RCD protection matters for EV circuits specifically.
PEN faults
A PEN (Protective Earth and Neutral) fault occurs on PME (Protective Multiple Earthing) supplies if the combined earth/neutral conductor is broken somewhere upstream, which can make exposed metalwork on your property live. This is a genuinely serious fault, and modern EV chargers include PEN fault detection specifically to protect against it by cutting power immediately if it's detected. See our guide on whether you need an earth rod for your EV charger for more detail on PME and PEN protection requirements.
Damaged cable
A cable with damaged insulation or a compromised earth conductor can cause exactly the kind of leakage an RCD is designed to detect. Inspect the full length of the cable, not just the ends, for cracks, cuts, or crush damage — this is a common and easily overlooked cause of intermittent tripping.
Vehicle fault
Occasionally the fault originates in the vehicle's onboard charger rather than the home charge point. If the charger trips with one vehicle but not another (or trips on your driveway but the same car charges fine elsewhere), the vehicle is the more likely source.
Supply problems
Voltage fluctuations, a failing connection at the consumer unit, or an ageing protection device nearing end of life can all cause nuisance tripping that isn't really about the charger or vehicle at all. If tripping affects other circuits in the property too, or started after other electrical work, the supply itself is worth investigating.
RCDs, RCBOs and PEN fault/surge protection devices, in stock with fast UK dispatch.
Shop protection devices →When to call an electrician
Never simply keep resetting a tripped RCD/RCBO repeatedly without investigating — a protection device that trips is doing its job, and repeated resets without finding the cause risks masking a genuine safety fault.
Frequently Asked Questions
Is it dangerous if my EV charger keeps tripping?
The tripping itself is a safety feature working as intended, not the danger itself — but it indicates an underlying fault that needs identifying. Repeatedly resetting the device without investigating the cause is not advisable, since it can mask a genuine and potentially serious electrical fault.
Why does my charger only trip when it's raining?
This points to moisture ingress somewhere in the system — commonly the charger's enclosure seal, a cable gland, or the connector itself. Check the charger's IP rating is appropriate for its installation location and inspect enclosure seals for damage or wear.
What's the difference between a nuisance trip and a genuine fault?
A nuisance trip happens without a real safety issue present, often due to marginal leakage current, an oversensitive or ageing device, or environmental factors like moisture. A genuine fault means there's an actual leakage or wiring problem. Since the two can look identical from the outside, any repeated tripping should be properly diagnosed by an electrician rather than assumed to be a nuisance trip.
Can a faulty EV charging cable cause an RCD to trip?
Yes. Damaged insulation or a compromised earth conductor in the cable can cause the exact current imbalance an RCD is designed to detect. Inspecting the full length of the cable for damage is a simple first step before assuming the fault lies with the charger or the property's wiring.
Further reading:
RCD trip sensitivity: 30mA vs 100mA vs 300mA
Do you need an earth rod for an EV charger?
Why won't my EV charge? (full troubleshooting guide)
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This guide provides general troubleshooting information. Testing, resetting, or replacing any protection device must be carried out by a qualified, registered electrician in accordance with BS 7671.